A thin Rihanna is unhappy with her size zero figure, and would like to have her fuller figure back, including her booty!

She told Us Weekly:

“I’m a size 0 – and not happy about it! I went way too far. I prefer myself a bit chunkier. I want my old butt back!”

With all the projects Rihanna has been working on like movies and her seventh CD, it’s not wonder she’s lost some weight — with all the stress from her hectic schedule and the training for her “Battleship” movie role.

The actress/singer said:

“I want to do two more [movies] before touring again next year. My schedule is crazy!”

Recently Rihanna suffered from exhaustion after her appearance at the Met Ball last month. Audience members looked worried about the slim-framed Barbadian beauty.  Rihanna confessed:

“I got no sleep [beforehand]. It’s harsh on your body!”